Rivera Thirty Twelve (R30) super Hum!

[Indyryder02]

The can of a radial capacitor is insulated from both of it's leads. What you measure on the can is incidental and not a reliable reading.
However, in this case, what you saw at the can of C11 lined up with it being missing it's ground connection.

Ok. That makes sense. It didn’t seem directly connected for sure. But interesting it was still able to see that difference.